Fabricated wooden I-beams each comprising a pair of wooden flanges and web members having longitudinal edges received in grooves of the flanges are becoming increasingly popular due to the rising costs of sawn lumber and the scarcity of good quality wood capable of producing beams of large size. The fabricated wooden I-beams require less wood and also reduces the costs of transportation due to their lower weight. Wooden I-beams of this type have been disclosed extensively in the prior art with exemplary patents being U.S. Pat. Nos. 3,490,188, 4,074,498, 4,191,000, 4,195,462, 4,249,355, 4,336,678, 4,356,045, 4,413,459, 4,456,497 and 4,458,465.
Prior known procedures for forming fabricated wooden I-beams by gluing the members together have generally entailed the use of various conveyor and drive assemblies in which a series of webs are driven along a web conveyor line in either spaced or end-to-end abutting relationship, with a pair of grooved flanges driven along opposite sides of the web conveyor. The flanges are driven with their grooves facing the webs and are gradually converged toward the conveyed webs so that the longitudinal web edges, usually pre-glued, enter the grooves to form an interconnecting glued joint therebetween.
In most prior art arrangements of which we are aware, the flange drive roll assemblies engage the narrow faces of the flanges which result in poor surface contact and inadequate or inefficient control over traction forces.
Another problem with prior art systems of which we are aware is that the flanges are typically conveyed through the machine in which flange bottom support is provided with horizontal rolls. At higher speeds of operation, these rolls tend to create undesirable vibration which causes the flanges to bounce. This may result in mis-alignment with the plane along which the webs are conveyed.
In most prior art assembly lines of which we are aware, one of the machine sides is fixed while the other machine side is laterally movable to provide for lateral adjustment for different web widths. This type of system necessitates the use of web drive systems which are formed with universal spline joints and therefore necessitate the need for sliding spline drives. This unnecessarily increases the cost and sophistication of the machine.
Another significant problem associated with prior art assembly lines of which we are aware is that the various web and flange drive systems are extensively manually adjusted prior to any particular production run and there exists no control system associated with the machine to allow for repeatability in performance. Therefore, there exists difficulty in the ability to replicate and control the manufacturing process.
It is accordingly one object of the present invention to control the forces against the webs and against the flanges with the web and flange drives to obtain uniform, repeatable and adequate force applications.
Another object is to control the process to ensure that the outfeed is running at a substantially constant velocity while regulating the forces and the speed at which the webs and flanges are driven and compressed together.
Another object is to control the web and flange infeed and outfeed drives with hydraulically operated motor drives that have closed loop servo controls utilizing encoders to sense velocity and hydraulic pressure transducers to sense torque loading.
Still a further object is to utilize simple and easy to operate adjustment mechanisms to accommodate webs of different width and thickness and different flange sizes.
Still a further object is to improve traction forces driving the flanges through the system and to provide for the smooth flow of flanges with minimum bounce and vibration.